New study shows how blood tests could help doctors spot high-risk patients early
Paraquat is a powerful weed killer that’s been used around the world for decades. But it’s also one of the most dangerous poisons for humans. Even small amounts can cause serious damage to the lungs and other organs, and tragically, many people don’t survive after swallowing it—whether by accident or in suicide attempts. Right now, there is no antidote for paraquat poisoning, and doctors often struggle to predict who will recover and who won’t.
A new study from researchers at Ningbo University in China offers a new way to help. The team found that by looking at certain immune cells in the blood, doctors might be able to tell early on which patients are at greater risk of dying. This discovery could lead to better, faster care and possibly help save lives.
Why Is Paraquat So Deadly?
Paraquat is fast-acting and very effective at killing plants. But in people, it causes damage mostly by creating toxic molecules called free radicals, which harm cells—especially in the lungs. Breathing becomes difficult, and other organs start to fail. Sadly, up to 90% of people who swallow paraquat die, often within days.
Over the years, scientists have studied many parts of how paraquat harms the body. But until now, there hasn’t been much research on how it affects the immune system—the body’s defense against illness.
What Did the Researchers Do?
The research team looked back at medical records from 92 people who were treated for paraquat poisoning between 2016 and 2021. They analyzed each person’s blood test results from the first day they arrived at the hospital, paying close attention to their immune cells.
They tracked what happened to each patient over the next 90 days, then compared the blood data from those who survived to those who didn’t.
The Key Immune Cells That Made a Difference
The scientists found some important patterns:
- People who had more lymphocytes (a type of white blood cell) were more likely to die.
- A higher ratio of CD4 to CD8 T cells (two types of immune cells that help fight infection) was linked to worse outcomes.
- Those with fewer natural killer (NK) cells—immune cells that destroy harmful cells—had a higher risk of death.
- High neutrophil counts, another type of immune cell that responds to injury, also predicted worse survival.
These four factors—lymphocytes, T cell ratio, NK cells, and neutrophils—stood out as strong, independent predictors of whether a patient would survive or not.
A Tool to Predict Risk
Using this information, the team created a visual tool called a “nomogram” that turns lab test results into a simple score. That score can help doctors quickly estimate a patient’s chance of survival.
The tool was tested and found to be highly accurate. In fact, it correctly predicted outcomes over 90% of the time in this group of patients.
Why This Matters?
When someone swallows paraquat, time is critical. Doctors need to make decisions fast—about whether to move the patient to intensive care, start certain treatments, or prepare for the worst. But without clear indicators, those decisions can be incredibly difficult.
This study offers a new way to guide those early decisions. By running standard blood tests and checking specific immune cell levels, doctors could get a much clearer picture of the patient’s risk—within the first 24 hours.
Are There Any Limits?
Yes, the study had some limitations. For example, it only looked at relative levels of immune cells (not the total number), and it only measured them once—on the first day. It also focused on short-term survival, not long-term effects like lung damage that can appear later.
Still, this is one of the first human studies to look at the immune system’s role in paraquat poisoning. It adds an important piece to the puzzle and opens the door to more research.
Final Thoughts
While we still don’t have a cure for paraquat poisoning, this study brings us a step closer to saving more lives. By paying attention to the immune system’s response, doctors may soon have better tools to predict outcomes, tailor treatments, and give patients a fighting chance.
The translation of the preceding English text in Chinese:
新研究显示血液检测或可帮助医生及早发现高危患者
百草枯是一种强效的除草剂，几十年来在全球范围内广泛使用。但它同时也是对人类最致命的毒物之一。即使是少量摄入，也可能对肺部和其他器官造成严重损害，令人痛心的是，无论是意外还是自杀尝试，许多吞服百草枯的人最终都无法存活。目前，百草枯中毒尚无特效解毒剂，医生往往难以判断哪些患者能够康复，哪些则不幸罹难。
中国宁波大学的研究人员进行的一项新研究提出了一种新的辅助方法。研究团队发现，通过观察血液中的某些免疫细胞，医生可能可以在早期识别出死亡风险较高的患者。这一发现有望带来更迅速、更有效的救治，甚至挽救生命。
百草枯为何如此致命？
百草枯作用迅速，对植物杀灭力极强。但在人体内，它主要通过产生被称为自由基的有毒分子造成伤害，这些分子会破坏细胞，尤其是肺部细胞。患者会出现严重呼吸困难，随后其他器官也可能衰竭。遗憾的是，多达90%的百草枯摄入者最终死亡，很多人在数日内便不治身亡。
多年来，科学家已经研究了百草枯对身体造成损伤的多个方面。但迄今为止，关于它如何影响免疫系统的研究却较为稀少。免疫系统是人体抵抗疾病的重要防线。
研究人员做了什么？
研究团队回顾了2016年至2021年期间92名因百草枯中毒入院治疗的患者病历。他们分析了患者在入院第一天的血液检查结果，特别关注免疫细胞的情况。
研究人员随后追踪这些患者90天内的生存情况，并对比生还者与不幸去世者的免疫细胞数据。
决定生死的关键免疫细胞
科学家发现了几个显著的模式：
-
淋巴细胞（一种白细胞）数量较多的人更容易死亡；
-
CD4与CD8 T细胞比值较高（这两种T细胞均参与免疫反应）也与较差的预后相关；
-
自然杀伤（NK）细胞数量较少的患者，其死亡风险更高；
-
中性粒细胞（另一类参与损伤应答的免疫细胞）数量较高也预示生存几率较低。
这四项指标——淋巴细胞、T细胞比值、NK细胞和中性粒细胞——被认为是独立且强有力的死亡风险预测因素。
预测风险的工具
研究团队基于这些指标开发了一种名为“列线图（nomogram）”的可视化工具，该工具可将实验室检测结果转换为简单的风险评分，帮助医生快速评估患者的生存可能性。
该工具经过验证，准确性极高——在这组患者中预测结果的准确率超过90%。
这项研究有何意义？
当有人吞服百草枯时，时间就是生命。医生需要迅速决定是否转入重症监护、是否启用特定治疗，或准备应对最坏的情况。但缺乏明确指标时，这些决策往往非常困难。
本研究为这些早期决策提供了新思路。通过进行常规血液检测并查看特定免疫细胞的水平，医生可以在最初24小时内获得更清晰的患者风险评估。
这项研究有哪些局限性？
当然，该研究也存在一些局限。例如，它只分析了免疫细胞的相对水平（而非总数量），并且只在入院首日采样一次。研究也仅聚焦于短期生存率，并未评估如肺损伤等长期后遗症。
尽管如此，这仍是首批研究百草枯中毒中免疫系统作用的人体研究之一，为了解这一过程提供了关键线索，并为未来研究打开了大门。
总结
尽管目前我们仍无百草枯中毒的特效疗法，但这项研究使我们向挽救更多生命迈出了关键一步。通过关注免疫系统的反应，医生可能很快就能获得更好的工具来预测预后、制定个性化治疗方案，并给予患者真正的生存希望。
Reference:
Qian Dong, Huan Xu, Pengjie Xu, Jiang Liu
Lymphocyte subsets predict mortality in acute paraquat poisoning.
Biomol Biomed [Internet]. 2025 Feb. 18 [cited 2025 Apr. 16];
Available from: https://www.bjbms.org/ojs/index.php/bjbms/article/view/11891
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Editor: Merima Hadžić
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